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SEWAGE TREATMENT PLANTS

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					                                                        Report
                                                            from the
                                        CHESAPEAKE BAY FOUNDATION




    SEWAGE TREATMENT PLANTS:
 THE CHESAPEAKE BAY WATERSHED’S
SECOND LARGEST SOURCE OF NITROGEN
           POLLUTION

      Most Plants Don’t Utilize Available Technology
              To Reduce Nitrogen Pollution




                     October 29, 2003
                    Embargoed until 12:01 am on October 29, 2003



BACKGROUND
For 20 years, Chesapeake Bay scientists have known that nitrogen pollution is the most
significant problem facing the Bay, degrading habitat for key plants and animals in the
Bay’s ecosystem, including underwater grasses, crabs and oysters. In 2003, the
Chesapeake suffered one of the largest “dead zones” (areas of low or no dissolved
oxygen) on record, stretching at one point 150 miles from Baltimore to the York River.
Excess nutrients were one of the leading culprits along with climatic factors. Low
dissolved oxygen levels are also a problem in many tributaries. Existing dissolved
oxygen standards, adopted by the Bay states under the federal Clean Water Act, are
violated routinely. As a result of nitrogen pollution, the Chesapeake Bay now functions
at barely one-quarter of its estimated potential.

In 1998, a majority of the mainstem of the Bay and major parts of its tidal tributaries
were added to Virginia and Maryland’s “Impaired Waters List” (also known as the EPA’s
“Dirty Waters List”). Earlier this year the Chesapeake Bay Program determined that
water quality would improve and substantial progress could be made toward removing
the Bay from the “Dirty Waters List” if nitrogen pollution was reduced by 110 million
pounds per year.

Nitrogen entering the Bay from sewage treatment plant (STP) effluent, agriculture, air
deposition and urban runoff, and other sources stimulates “blooms” (population
explosions) of microscopic plants called algae. While they are alive and drifting in the
water column, the algae decrease water clarity, blocking sunlight from underwater Bay
grasses. When algae die, they sink to the bottom, and the bacterial process of decay
removes oxygen from the water.

Wastewater discharged from sewage treatment plants is the second largest source of
nitrogen pollution to the Chesapeake Bay1. When approximately 12 million of the 16
million residents of the watershed flush their toilets, the wastewater goes to STPs, which
discharge into the Chesapeake Bay and its tributaries.

There are 304 “significant” STPs in the watershed, which discharge 1.5 billion gallons of
wastewater each day. These plants contribute about 52 million pounds of nitrogen
pollution annually to the Bay and its tributaries. To date, more than two-thirds of those
plants do not use any technologies to remove nitrogen pollution, and only ten plants are
currently reducing nitrogen pollution to state-of-the-art levels, according to the most
recent data available (2002).




1
  Agriculture contributes 42% of the nitrogen loading and is the largest source of nitrogen pollution to the
Bay. CBF is working on both the voluntary and regulatory fronts to secure the necessary nitrogen
reductions from agriculture.
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STPs that do not include nutrient removal technologies have wastewater discharge
concentrations of approximately 18 milligrams of nitrogen per liter (18mg/L) or more.
With advanced applications of Nutrient Reduction Technology (NRT) or Biological
Nutrient Removal (BNR), plants can reduce discharge concentrations to 3 mg/L or less.
Upgrading the watershed’s “significant” STPs with advanced BNR would reduce their
collective discharge of nitrogen from 52 to 13 million pounds. This 39-million-pound
reduction alone would account for more than one-third of the 110 million pound/yr
nitrogen reduction goal that scientists believe will make substantial progress toward
meeting the commitments of Chesapeake 2000, the current multi-jurisdictional Bay
agreement.

EPA has recently confirmed that the states currently have the authority and obligation to
set permit limits for nitrogen pollution from STPs. To date, however, the states have
written few permits with such limits.

STPs BY STATE
Table 1 presents the number of “significant” STPs by jurisdiction. The definition differs
slightly by state, but in general, a “significant” discharger either:
   ! Discharges more than 0.5 million gallons per day (MGD);
   !   Discharges less than 0.5 MGD but is located below the fall line and therefore has
       a more direct impact on water quality in tidal tributaries or the Bay main stem;
   ! Discharges 0.4 MGD or more in Pennsylvania.


Table 1: Number of STPs by Jurisdiction
Jurisdiction    # Of Significant Facilities

                                                  STP ASSESSMENT
     DC                      1                    The Chesapeake Bay Foundation
  Maryland                  65                    conducted a review of the most recent STP
                                                  data available from the Chesapeake Bay
  Virginia                  81                    Program (2002 reports) from Maryland,
Pennsylvania                123                   Virginia, Pennsylvania, and the District of
                                                  Columbia. The loads from the STPs in
West Virginia                9
                                                  these four jurisdictions are about 94% of
  Delaware                   3                    the total nitrogen load from all STPs in the
                                                  Bay watershed.
 New York                   22
                                               Each plant was evaluated based on the
                                               annual average concentration of total
  TOTAL                     304                nitrogen in the plant’s discharge. A plant
                                               was rated as “Excellent” if it achieved 3
mg/L or less, “Good” if the nitrogen pollution was between 3.1 to 5 mg/L, “Needs
Improvement” if it ranged from 5.1 to 8 mg/L, and “Unsatisfactory” if it discharged > 8.1
mg/L. Table 2 presents the total number of “significant” dischargers in each total nitrogen
concentration grade category by state.
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Bay Program models show that significant reductions in nitrogen pollution from
agriculture, air deposition, stormwater management and STPs, will still not be enough to
achieve the Chesapeake 2000 goal. That is why CBF scientists believe it is critical that
STPs decrease their total nitrogen concentrations to 3 mg/L or less. Table 2 shows that
about 96% of the plants do not meet the 3 mg/L concentration level.
Table 2: Number of Plants by Total Nitrogen Concentration (annual average)
State Excellent         Good              Needs                Unsatisfactory   Data Not
                                       Improvement                              Available
        < 3 mg/L       3.1 – 5         5.1 – 8 mg/L             > 8.1 mg/L
                       mg/L
 DC                                            1
MD          5            9                  17                         32          2
 VA         2            5                  15                         59
 PA         3            7                  13                         97          3
Total      10            21                 46                         188         4


While some improvements at STPs have been made since 2002, and other improvements
can be expected in the next few years, Chesapeake 2000 commitments cannot be met and
the health of the Chesapeake Bay cannot be significantly improved without tremendous
improvements in removing nutrients by all nitrogen load sources. This includes
implementing state-of-the-art technology at “significant” STPs.

NITROGEN LOADS AND CONCENTRATIONS FROM STPs
When analyzed by the concentrations of nitrogen and the volume of wastewater
discharged into the Chesapeake Bay, it is clear that the few plants operating to remove
nitrogen pollution to the 3 mg/L concentration level treat only a very small percentage of
total STP wastewater.

             Figure 1: Volume of Wastewater Discharged by
                      Total Nitrogen Concentration
                      1000
                                                                867
                       800
    Million gallons    600
                                                        474
        per day        400
                       200
                                 26       58
                         0
                                 <3     3.1-5          5.1-8   > 8.1
                                      Nitrogen Concentration mg/L




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Figure 1 shows that less than 2% of the wastewater flow is treated to the 3 mg/L
concentration level, which CBF believes will be necessary to restore the Chesapeake Bay.

An important point about nitrogen loads from STPs is that with the watershed's
population projected to grow by 1 million to 17 million people by 2010, the associated
nitrogen load from STPs will increase unless the plants reduce the total nitrogen
concentration in their discharges.

Table 3 clearly illustrates the necessity for reducing nitrogen concentration in order to
significantly reduce nitrogen loads (total pounds) to the Bay. The table compares the
amount of flow (million of gallons of wastewater discharged per day or MGD) and total
nitrogen loads (pounds per year) within each concentration category. For example,
compare the “Needs Improvement” and “Unsatisfactory” categories. Note that while the
“Unsatisfactory” category has approximately twice as much flow, its total nitrogen load
is more than 4 times higher than the “Needs Improvement” category. This explanation is
simple: plants in the “Unsatisfactory” category do a much poorer job of removing
nitrogen from their discharges. “Unsatisfactory” plants contribute 61% of the flow from
all of the Bay’s STPs, yet they contribute 80% of the total nitrogen load. Reducing their
concentrations to 3 mg/L would slash their contribution to the Bay’s nitrogen load by
85%.

Table 3: Total Nitrogen Flow (MGD) and Load (pounds per year) by Concentration
Category
                              GOOD         NEEDS
                                        IMPROVEMENT UNSATISFACTORY
         EXCELLENT           (3 – 5.0
            (< 3 mg/l)        mg/l)      (5.1 – 8 mg/l)    (> 8.1 mg/L)    TOTAL FLOW TOTAL LOAD

      Flow        Load     Flow Load Flow       Load      Flow   Load
DC                                      312.0 6,177,288                       312.0    6,177,288
MD     8.8       72,065    35.6 461,272 65.5 1,425,576 228.1 8,458,235        337.9    10,417,148
VA     1.5        6,912    12.5 157,269 62.5 1,239,889 421.2 21,821,442       497.8    23,225,512
PA     16        47,708    10 128,304 34      767,887     218 10,777,520      277.5    11,721,419
Total 26.0       126,685   58.4 746,845 473.9 9,610,640 866.8 41,057,196     1,425.1   51,541,367



STPs– TOTAL NITROGEN LOAD BY COUNTY
Appendix A provides a listing of STPs by state, grouped by average nitrogen discharge
concentrations for 2002. The 10 plants that are achieving 3 mg/L total nitrogen or less
are listed in Table 4. Clearly, the record of these 10 plants demonstrates that total
nitrogen concentrations of 3 mg/L or less can be achieved with currently available
technology. For some plants, space limitations may make achieving this goal more
difficult.



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      Table 4: STPs Achieving Average Total Nitrogen Concentrations Less Than 3 mg/L
      – 2002 data
State Facility               County          Flow       TN Concentration TN Load
                                             (MGD)           (mg/L)         (Pounds per
                                                                            year)
MD     Fort Meade            Anne Arundel       1.8             2.3               12,222
       Chesapeake Beach      Calvert            0.7             2.6                5,350
       MD Correctional Inst. Washington         1.0             2.5                7,126
       Taneytown             Carroll            0.6             2.7                4,771
       Broadneck             Anne Arundel       4.8             2.9               42,595
VA     Farmville             Prince Edward      0.9             0.5               1,488
       Remington Regional     Fauquier          0.6             2.9               5,424
PA     Marysville            Perry              0.6             0.7                1352
       Upper Allen           Cumberland         0.5             1.6               2,436
       Township
       Gregg Township        Union              0.7             2.9               5,906



      STP – NITROGEN LOAD AND CONCENTRATION BY COUNTY
      These data are presented in Appendix B. There are 15 counties with STP discharges to
      their waterways of over a million pounds of nitrogen per year.
          • The 50 plants in the counties with STP discharges of over a million pounds
             generate 597 MGD of wastewater, or 42% of the total flow from STPs, and over
             29 million pounds, or 56% of the total nitrogen load from STPs each year.
          • The average concentration of these plants is 17.4 mg/L, well into the
             “Unsatisfactory” category.
          • Most of these large plants are concentrated in densely populated areas, so their
             combined effluents contribute a great deal of stress to local waterways as well as
             to the Bay.

      These plants have the potential to play powerful roles in cleaning up the Chesapeake
      system, if they are made priorities for upgrades. For example, in Maryland the two plants
      with the most loads both discharge into Baltimore area waters. In Virginia, plants in
      Alexandria, Arlington, and Fairfax join Blue Plains in the District of Columbia to
      discharge to the Potomac. Also in Virginia, the waterways of Hampton Roads receive a
      large collective load of nitrogen from plants in Hampton, Newport News, Virginia Beach,
      Norfolk, Portsmouth, Chesapeake, and Suffolk. In Pennsylvania, the Lancaster - York -
      Dauphin County area generates a great deal of the flow and load.




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UPGRADING STPS - THE TECHNOLOGICAL FIX: NRT/BNR
NRT/BNR technology was developed as a cost-effective way to reduce nutrient pollution
in the Chesapeake Bay watershed in the 1980s. At the plants that have this technology,
it has proven to be very effective. Sewage treatment plants that do not use NRT
technology for nitrogen removal will discharge, on average, 18 mg/L or more of total
nitrogen in their effluent. Fortunately, NRT/BNR technology is available to reduce
nitrogen effluent concentrations to 3 mg/L (average concentration over the course of a
year). This level of treatment is currently considered “state-of-the-art.”

Although the design, construction, and operation of BNR facilities are complex, the
underlying science of how they work is fairly simple. NRT and BNR use microorganisms
like bacteria to break down the organic material that contains nitrogen in wastewater. In
general, the water is pumped through a succession of tanks, alternating between ones that
contain oxygen and ones that do not. Within each tank are bacteria specifically suited for
survival under those conditions. The bacteria within the aerobic tanks (those containing
oxygen) have the ability to break down organic nitrogen and ammonia into nitrate (a
process referred to as “nitrification”). Then the organisms in the anoxic tanks (those
without oxygen) further break down the nitrate into nitrogen gas by stripping the oxygen
from the nitrates (a process referred to as “denitrification”). The nitrogen gas escapes
harmlessly into the atmosphere.

To date, most STPs that have implemented NRT/BNR technology are not designed to
operate at peak effectiveness and do not reduce effluent nitrogen concentrations to 3
mg/L. There are no watershed-wide requirements to reduce nitrogen pollution, and the
states have, except in a few instances, failed or refused to impose adequate,
enforceable total nitrogen effluent limits on STPs. For example, in Virginia, sewage
treatment plants that have accepted state cost-share money to install NRT/BNR are
required only to reduce nitrogen total concentrations to 8 mg/L, and there is no incentive
to go further.

As we work to reduce nitrogen loading from all sources, it is critical that STPs implement
these upgrades to achieve their share of the overall reductions. After achieving their
share, additional reduction of nitrogen pollution by STPs could alleviate the need for
even more expensive reductions that municipalities need to undertake to reduce
stormwater runoff from urban areas, which includes a significant nutrient component.

THE COSTS OF UPGRADING
While there have been a number of estimates on the cost of upgrading the watershed’s
STPs, it is very difficult to come up with a firm estimate for costs on which everyone
agrees. Maryland’s Department of the Environment has estimated the cost of upgrading
plants in Maryland at between $5 and $14 per household per year.
The Chesapeake Bay Program assembled a task force of representatives from local, state
and federal government, municipal wastewater agencies, and consultants who specialize
in nutrient reduction technology. This task force issued a report in November 2002 titled
Nutrient Reduction Technology Cost Estimates for the Point Sources in the Chesapeake
Bay Watershed. The report concluded that the cost for upgrading all of the Bay’s

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“significant” sewage treatment plants to a nitrogen concentration of 5 mg/L and 3 mg/L is
$2.7 and $4.4 billion respectively. While the estimated range for these upgrades is large,
the costs can be minimized if STPs implement upgrades to the NRT/BNR process while
undertaking routine capital improvements.

THE NEXT STEPS
Key steps to achieving the Chesapeake 2000 nutrient reduction goals are:
   ! Ensure the implementation of measures to achieve the Chesapeake Bay Program’s
     basin-specific nitrogen reduction goals in each state, achieving as much of each
     basin’s reductions from sewage treatment plants as possible.
   ! On state and federal levels secure new legislation, regulations, guidance, or policy
     direction supporting enforceable 3-mg/L total nitrogen permits limits for the most
     “significant” STPs in the watershed.
   ! Secure “binding” commitments at either the federal (EPA) or state level
     (Governor, Secretariat, legislature or state agency) that guarantee widespread
     implementation of Nutrient Removal Technologies/Biological Nutrient Removal
     and nutrient pollution permit limits at sewage treatment plants throughout the Bay
     watershed.

Clearly, STPs can reduce nitrogen loads significantly by using available technology.
This reduction is not occurring throughout the watershed at the rate needed to meet the
goals of Chesapeake 2000 by 2010. The lack of timely action creates the need for
binding commitments to serve as the driving force for sewage treatment plant upgrades
and increased funding. Such commitments can be achieved in numerous ways, including:
state or federal requirements on sewage treatment plant discharges (nitrogen effluent
limits or technology requirements); Governors’ Executive Orders or state policies issued
by Natural Resource or Environmental Protection Secretaries; or new laws, regulations,
policies, or guidelines.

CBF is committed to obtaining the nutrient reductions necessary from all sectors,
including agriculture, STPs, stormwater runoff, air deposition, and other major
contributors of nutrient load, in order to remove the impairment to the Chesapeake Bay.
Upgrading wastewater treatment plants with NRT is a reasonable, proportional, and
achievable step toward that end.




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